The common notchbacks have open rear truck bed which offers a poor protection for goods during transportation. People therefore install a movable cover to cover and close the rear truck bed and remove the cover only when goods are comparatively high. Existing covers made of glass fiber reinforced plastic (resin) or thermoplastic plastics are very inconvenient for use due to the following reasons: the cover made of glass fiber reinforced plastic (resin) must have a certain thickness to ensure sufficient strength. If the cover is too thick and heavy, it will affect its opening/closing flexibility and oil consumption for the vehicle, as well as have a high requirement for the actuating mechanism. The cover made of thermoplastic plastic is a hollow structure and quite thick, occupying too much room of the rear truck bed with its appearance hardly matching that of the vehicle body.